The basis for this additional volume are the three volumes of the handbooks Dictionaries. An International Encyclopedia of Lexicography (HSK 5.1-5.3), published between 1989 and 1991. An updating has been perceived as an important desideratum for a considerable time. In the present Supplementary Volume the premises and subjects of HSK 5.1-5.3 are complemented by new articles that take account of the practice-internal and theoretical developments of the last 15 years. Special attention has been given to the following topics: the status and function of lexicographic reference works, the history of lexicography, the theory of lexicography, lexicographic processes, lexicographic training and lexicographic institutions, new metalexicographic methods, electronic and, especially, computer-assisted lexicography.